Lubricant



Patented Nov. 26, 1940 PATENT OFFICE LUBRICANT Carl F. Prutton,Cleveland Heights, Ohio, assignor to The Lubrl-Zol Corporation,Wicklifl'e, Ohio, a corporation of Ohio No Drawing. Application Decemberl2, 1938, Serial No. 245,226

25 Claims. ((1 252-39) This invention relates, as indicated, tolubricating compositions and more particularly to lubricatingcompositions which are predominantly hydrocarbon oil, the properties ofwhich affect- 5 ing its use for particular purposes are improved by theaddition of materials which are particularly effective in rendering thelubricants suitable ior use under conditions of extreme stress asimposed by high temperatures, high loads, etc.

In my co-pending applications, Ser. Nos.

737,070, filed July 26, 1934, and 216,153, filed June 27, 1938, I havedisclosed a broad class of lubricating compositions of general utility,particularly in the field of use where extreme pressures areencountered.

My present invention relates to the discovery that a certain class ofsuch materials is particularly suitable for use in lubricants subjectedto conditions of extreme stress such as those involved in thelubrication of heavily loaded gears, and in the lubrication of internalcombustion engines operating under severe service conditions; forexample, those encountered by internal combustion engines particularlyof the aviation and Diesel types.

It is the principal object of my invention, therefore, to provide alubricating composition which is especially suited for the purposesdescribed.

Other objects of my invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention,then, consists of the means hereinafter fully described and particularlypointed out in the claims; the following description setting forth indetail certain approved combinations of ingredients embodying myinvention, such disclosed means constituting, however, but one ofvarious forms in which the principle of the invention may be used.

Broadly stated, this invention comprises the provision of a lubricatingcomposition for the purposes specified, characterized by the fact thatthe same contains a lubricating oil, preferably of the hydrocarbon type,as a major constituent with the properties or such composition affectingits use as a lubricant, especially under the conditions specified, bythe incorporation therein 50 of a minor amount, based on the amount oflubricating oil present, of a stable, oil-soluble salt of an aromaticacid.

More especially, my invention comprises the discovery that salts ofaromatic acids of the type 55 which may be produced by condensing anaromatic compound with a long-chain fatty acid, are particularly suitedfor use.

The lubricating oil which may be employed as the-base for my compositionis preferably a hydrocarbon lubricating oil, whether naturally occurringor synthetic, and including hydrogenated oils. The base oil ispreferably a refined mineral lubricating oil of the character which willnot readily decompose under conditions of extreme stress such as highpressures and high temperatures. The mineral oil base may haveincorporated therein such constituents as are usually employed for thepurpose of improving its pour-point, etc., as well as constituents whichare added to prevent oxidation and sludging. In general, thecommercially available materials for this purpose will be found entirelycompatible with the, addition agent which characterizes the compositionsof my invention.

As above indicated, the addition agents which characterize thecompositions comprising my invention may be broadly defined as salts ofarcmatic acids of the type which may beproduced by condensing anaromatic compound with a long-chain fatty acid.

For certain purposes, the addition agent may advantageously contain anelement of the type represented by: the halogens; sulphur, selenium andtellurium; phosphorus and arsenic. When maximum stability is desired,the halogen is preferably attached to a benzenoid ring such as thearomatic nucleus of the compound.

Specific examples of salts which, as above indicated, are disclosed inmy previously identified earlier applications and which arerepresentative 5 of those which are useful in preparing the compoundedlubricants of my invention are:

Aluminum phenyl mercapto stearate Aluminum phenyl stearate 40 Calciumphenyl mercapto stearate Calcium phenyl stearate Sodium phenyl mercaptostearate Sodium phenyl stearate Zinc phenyl stearate 45 and halogenderivatives of the above such as:

As above indicated, the aromatic acids used in the preparation of thesesalts are of the type which may be produced by condensing an aromaticcompound with a long-chain fatty acid. When the addition agent containsa halogen, it may be conveniently prepared by condensing a halogenatedaromatic compound with a longchain fatty acid.

The condensation reaction by which the arcmatic acids referred to may beformed may be of the type in which the fatty acid is unsaturated, thatis, contains at least one pair of multiplebonded carbon atoms such asthe following groups:

-CH=CH and CsC- or of the type in which the fatty acid has beenhalogenated: that is, contains a halogen substituent. In either case,the condensation reaction is carried on in the presence of a catalyst ofthe type represented by anhydrous aluminum chloride, anhydrous ferricchloride and the addi tion products formed in the reaction of suchanhydrous chlorides with oleflnes, such as ethylene.

For further definition of the catalyst which may be employed, referencemay be had to my aforesaid co-pending application Sqrial No. 216,153,page 4, lines 8 to inclusive.

While the addition agents contemplated for use in my compoundedlubricants may be prepared by forming a salt of an aromatic acidproduced by the condensation reactions described, it is also possible,in certain'cases, to produce such addition agents by reacting a salt ofa longchain fatty acid with an aromatic compound in one of the followingways:

1. A salt of a long-chain unsaturated fatty acid may be condensed withan aromatic compound in the presence of a catalyst, for example: thecondensation of aluminum oleate with chlorbenzene in the presence ofanhydrous aluminum chloride.

2. A salt of a halogenated long-chain fatty acid may be condensed with ahalogenated aromatic compound by means of an alkali metal in accordancewith the Wurtz-Flttig reaction, for example: the condensation of zincchlor stearate with ortho-di-chlorbenzene with metallic sodium.

3. A salt of a halogenated long-chain fatty acid may be reacted with ametallic aromatic compound, such as sodium phenyl, sodium phenate andthe like.

The long-chain fatty acid which may be employed in the preparation ofthe aromatic acids, the salts of which are used as addition agents in mycompounded lubricants, may contain substituent groups, such as thoselisted in my copending application, Serial No. 216,153, in Table No. 1on page 6.

The aromatic compounds suitable for use in a condensation reaction inthe preparation of these materials in addition to the hydrocarbonaromatic compounds include oxygen-substituted aromatic hydrocarbons, aswell as aromatic compounds containing other substituent groups, such asthose listed in application Serial No. 216,153 in Table No. 5, on pages11 to 14.

The following is a list of suitable aromatic compounds which may beemployed as constituents in the preparation of the aromatic acids, thesalts of which are used as addition agents in my compounded lubricants:

Benzene Toluene Xyienes Ethylbenzenes Naphthalene Methyl naphthalenesEthyl naphthalenes Anthracene Retene Diphenyl Benzophenone AnthraquinoneDiphenylether Salicylic acid Triphenyl phosphate Triphenyl phosphiteIricresyl phosphate Phenyl cyclohexane Diphenyl ether Chlor-naphthalenesChlor-benzenes Chlor-diphenyls Chlor-diphenyl ethers Chlor-benzophenonesBenzonitrile Methyl salicyiate Methyl chlorsalicylates Retene oil Amongthe suitable fatty acids which may be employed as constituents in thepreparation of the aromatic acids, the salts of which are employed asconstituents in my compounded lubricants, are the following:

Long-chain unsaturated fatty acids, such as:

Oleic acid Elaidic acid Linoleic acid Linolenic acid Elaeostearic acidStearolic acid Ricinoleic acid Any of the above acids which have beenhalogenated.

Halogenated long-chain saturated fatty acids,

such as:

Chlorinated lauric acid Chlorinated palmitic acid Chlorinated stearicacid Chlorinated mercapto oleic acids Chlorinated mercapto stearic acidsChlorinated hydroxy stearic acids Chlorinated thio-stearic acids Thevarious salts contemplated for use in the compounded lubricants of myinvention are the ammonium, substituted ammonium, potassium, sodium,calcium, barium, strontium, magnesium, aluminum, zinc and lead salts ofthe aromatic acids above identified.

In view of the particular uses for which my compounded lubricants areintended, it is apparent that of the salts included in the foregoingenumeration of the addition agents which may be employed, those whichare readily oil-soluble are the ones preferred for use. When thesecompounded oils are designed for use under conditions where hightemperatures are usually encountered, the addition agents should bestable at elevated temperatures. For use in crankcase lubricants forinternal combustion engines, they when the lubricating composition isexposed to temperatures up to 250 1".

The addition agents which are to be selected from the class describedshould be such that they are relatively non-corrosive with respect tothe metallic surfaces with which they come in contact during use.Certain of the named addition agents may be found to be detrimentallycorrosive to ertain sensitive bearing metals, in which case anappropriate corrosion inhibitor may be employed in conjunction therewithin the composition.

A lubricating composition prepared in accordance with my invention andwhich is predominantly hydrocarbon oil may contain from an effectiveamount to 20% of thesalt addition agent above identified. In general, itwill be found that.

an amount as low as .l% will often be quite effective and that amountsin excess of 10% are seldom necessary. A preferredrange ofconcentrations for the salt in the oilis from .5% to about 2%.

It is also within the contemplation of this invention to provide theaddition agents in the form of a concentrate in a suitable oil, said oilcontaining rather high percentages of the addition agents. Suchconcentrates may be employed for further blending with a lubricating oilin the proportions desired for the particular conditions of use.

While mineral oil, generally, is the principal ingredient of thelubricant, it is not essential that it be the only ingredient other thanthe addition agent, provided that there be no additional ingredientwhich is incompatible with such addition agent. It is within thecontemplation of this invention to include, if necessary or desirable,such other addition agents as are commonly added to improve theviscosity index or cold test of the lubricants; and a lubricatingcomposition according to this invention which also has a separatefilm-strength or oiliness increasing agent has been found to beespecially effective.

When used in conjunction with a hydrocarbon lubricating oil, it isobvious that, generally, only such amounts of the addition agent may bein-.

cluded as are soluble in the specified amount of oil. By the termsoluble", as herein used, it is intended to indicate the ability to formnot only true solutions but also any form of substantially permanentlyhomogeneous composition when incorporated in mineral oil. With most ofthe compounds there is usually little difllculty, especially if theincorporation is effected in the manner described in Cornell Patent No.2,042,880, and since quite small percentages often give remarkablyimproved results, it is seldom of extreme importance that the additionagents be oil-soluble in all proportions. Also, certain compounds are ofvalue as gelling or bodying agents when used in amounts greater than arestrictly soluble.

The addition agents above enumerated for use in my compounded lubricantsinclude certain ones which may be found to at least partially decomposeunder conditions of extreme stress such as the very high temperatureencountered in certain classes of use, while others are quite stableeven under such extreme conditions.

The use for which the lubricant is designed therefore determines theparticular type of addition agent to be selected. A certain amount ofdecomposition, which proceeds at a relatively slow rate, is usually notharmful. Care should be exercised, however, to select for a particularset of operating conditions, an addition agent which in the oil baseused, will not decompose under such operating conditions except at a lowrate.

By the term stable as used herein in describing the addition agents ismeant the characteristic of the addition agents which enables them toresist decomposition in the oil under the condition of use for which thelubricating composition is designed.

The lubricating compositions of this invention may be prepared by firstpreparing the salt and then dissolving the salt in the oil base, or theymay be prepared by reacting the acid in solution in all or a portion ofthe oil with a suitable basic compound in order to form the desired saltdirectly in solution in oil. In the latter case, it is frequentlydesirable to remove the water formed by the reaction, or which may havebeen added with the basic compound, by some means such as by heating atatmospheric or sub-atmospheric pressure.

In case the salt to be used is water-insoluble, an alternative procedureis as follows:

An aqueous, solution of a water-soluble salt of the acid is firstprepared, for example by dissolving the acid in an aqueous solution ofcaustic soda or caustic potash. The aqueous salt solution is thenemulsified with oil and a water-soluble salt containing the cation ofthe desired salt is added to the mixture. The desired salt is thusprecipitated from the aqueous medium and subsequently or simultaneouslydissolved by the oil medium. Separation of the aqueous and oil layers isthen effected for'example by settling or centrifuging. Subsequentwater-washing of the oil solution to remove traces of inorganic saltsmay be desirable, and removal of moisture may also be required.

This application is a. continuation-in-part of my aforesaid co-pendingapplications Serial Numbers 737,070 and 216,153, the latter being inturn a continuation in part of Patent No. 2,121,825 dated June 28, 1938,based on an application Serial No. 760,038, filed December 31, 1934.

Other modes of applying the principle of my invention may be employedinstead of the one explained, change being made as regards the materialsemployed, provided the ingredients stated by any of the following claimsor the equivalent of such stated ingredients be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition affecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount of mineraloil, of a stable, oil-soluble salt of an aromatic acid of the type whichmay be produced by condensing an aromatic compound with a long chainfatty acid.

2. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition affecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount of mineraloil, of a principal lubricating constituent a major amount 4 of minerallubricating oil with the properties of such composition aifecting itsuse as a lubricant improved by incorporating therein a minor amount,based on the amount of mineral oil, 01' a stable,'oil-soluble salt of anaromatic acid oi the type which may be produced by condensing ahalogenated aromatic compound with a long chain unsaturated acid.

4. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition affecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount of mineraloil, of

- a stable, oil-soluble salt of an aromatic acid of the type which maybe produced by condensing an aromatic compound with oleic acid.

5. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition affecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount of mineraloil, of a stable, oil-soluble salt of an aromatic acid of the type whichmay be produced by condensing a halogenated aromatic compound with oleicacid.

6. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition aflecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount of mineraloil, of a stable, oil-soluble salt of an aromatic acid 0! the type whichmay be produced by condensing a halogenated aromatic compound of thetype in which the halogen is attached to a benzenoid ring with oleicacid.

7. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition aifecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount of mineraloil, of

a stable, oil-soluble salt of an aromatic acid oi the type which may beproduced by condensing an aromatic compound with a mercapto fatty acid.

8. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition affecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount of mineraloil, of a stable, oil-soluble salt of an aromatic mercapto stearic acid.

9. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition aifecting its use as a lubricant improvedby incorporating therein a minor 'amount, based on the amount of mineraloil, of

a stable. oil-soluble salt of a halogen derivative of phenyl mercaptostearic acid.

10. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition affecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount of mineraloil, of a stable, oil-soluble halogen derivative of calcium phenylstearate.

11. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition airecting its use as a lubricant improvedby incorporating therein from about 0.10% to about based on the amountor mineral oil, of a stable, oil-soluble metallic salt of an aromaticacid of the type which may be produced by condensing an aromaticcompound with a long chain fatty acid.

12. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition afiecting its use as a lubricant improvedby incorporating therein from about 10 0.50% to about 2%, based on theamount of mineral oil, of a stable, oil-solublemetallic salt or anaromatic acid of the type which may be produced by condensing an.aromatic compound with a long chain fatty acid, which salt is 01' thetype in which the metal is in the divalent form.

13. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties 01' such composition affecting its use as a lubricantimproved by incorporating therein a minor amount, based on the amount ofmineral oil, of a stable, oil-soluble salt of an aromatic acid of thetype which may be produced by condensing a halogen bearing aromaticcompound with a long chain fatty acid,

l4. A lubricating composition containing as a principal lubricatingconstituent a major amount or mineral lubricating oil with theproperties of such composition ailecting its use as a lubricant improvedby incorporating therein from about 0.10% to about 10%, based on theamount of mineral oil, of a stable, oil-soluble salt of an aromatic acidof the type which may be produced by condensing an aromatic compoundwith a halogen bearing long chain fatty acid.

15. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition aflecting its. use as a lubricantimproved "by incorporating therein from about 0.50% to-about 2%, basedon the amount of mineral ,oil, of a stable, oil-soluble salt or anaromatic acid of the type which may be produced by condensing anaromatic compound with a halogen bearing long chain unsaturated acid.

16. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil withthe'propertles of such composition afl'ecting its use as a lubricantimproved by incorporating therein from about 0.10% to about 10%, basedon the amount of mineral oil, of a. stable, oil-soluble salt of anaromatic acid of the type which may be produced by condensing a halogenbearing aromatic compound with a halogen bearing long chain fatty acid.1

1'7. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition affecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount of mineraloil, of a stable, oil-soluble salt of a substituted phenyl stearic acid.

18. A lubricating composition containing as a principal lubricatingconstituent a major amount oi mineral lubricating oil with theproperties 01' such composition affecting its use as a lubricantimproved by incorporating therein a minor amount, based on the amount ofmineral oil, of a stable, oil-soluble salt of a halogen bearingderivative of phenyl stearic acid.

19. A lubricating composition containing as a principal lubricatingconstituent a major amount or mineral lubricating oil with theproperties of such composition aflecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount of mineraloil, of a stable, oil-soluble salt of chlor phenyl stearic acid.

20. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition aiiecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount oi mineraloil, of calcium chlor phenyl stearate.

21. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition aflecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount oi mineraloil, of aluminum chlor phenyl stearate.

22. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition aflecting its use'as a lubricant improvedby incorporating therein a minor amount, based on the amount oi mineraloil, oi a stable, oil-soluble salt of an aromatic acid of the type whichmay be produced by condensing an aromatic compound with a mercapto fattyacid.

23. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties or .such composition aflecting its use as a lubricantimproved by incorporating therein a minor amount, based on the amount oimineral oil, or a stable, oil soluble salt oi a phenyl mercapto' stearicacid.

24. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition affecting its use as a lubricant improvedby incorporating therein a minor amount. based on the amount or mineraloil, of a stable, oil-soluble salt or chlor phenyl mercapto stearlcacid.

25. A lubricating composition containing as a principal lubricatingconstituent a major amount of mineral lubricating oil with theproperties of such composition aflecting its use as a lubricant improvedby incorporating therein a minor amount, based on the amount of mineraloil, or calcium chlor phenyl mercapto stearate.

